Added a cityhash makefile.
Added a cityhash makefile.

google/gjstest,aungzanbaw/gjstest,aungzanbaw/gjstest,okdave/gjstest,aungzanbaw/gjstest,google/gjstest,okdave/gjstest,aungzanbaw/gjstest,okdave/gjstest,google/gjstest,google/gjstest,okdave/gjstest